c++ - 不调用QGraphicsSceneMouseEvent

当我单击场景时，什么也没发生。我用QMouseEvent和QGraphicsSceneMouseEvent尝试了多种方法，试图将焦点放在对象上，然后尝试单击它-没有结果。我也在其他人的帖子中寻找Internet上的解决方案，但没有找到任何适合我的方法。我在哪里犯错？

下面是一些代码：

这是我创建窗口，视图和对象的窗口之一，我想对鼠标事件做出响应：

TrackWindow::TrackWindow(Timers *timer)
{
timeLineBar = new QGraphicsScene(this);
timeLineBarView = new QGraphicsView(timeLineBar);
timeLineBarView->setFixedHeight(20);
timeLineBarView->setAlignment(Qt::AlignTop|Qt::AlignLeft);
timeLineBarView->setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
timeLineBarView->setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
timeLineBarView->setStyleSheet("background-color: #333333; border:none;");

QVBoxLayout *timeLineLayout = new QVBoxLayout;
timeLineLayout->addWidget(timeLineBarView);
timeLineLayout->addWidget(tracksTimelineView);
timeline = new TimeLine(timer);
timeLineBar->addItem(timeline);
//timeline->setFlag(QGraphicsItem::ItemIsFocusable);
//timeline->setFocus();
}

这是我的时间轴类的实现：

TimeLine::TimeLine(Timers *t)
{
    timer = new Timers;
    timer = t;
    timeLineWidth = 200000;
    timeLineScale = 0.1;
}

QRectF TimeLine::boundingRect() const
{
    return QRectF(0,0,timeLineWidth,18);
}

void TimeLine::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget)
{
    QRectF rect = boundingRect();

    QPen pen(Qt::NoPen);
    painter->setPen(pen);
    painter->setBrush(QColor(200,200,200));
    painter->drawRect(rect);

    for(int i=0;i<200;i++)
    {
        painter->drawText(i*30,9,QString::number(i+1));
    }

}

void TimeLine::mousePressEvent(QGraphicsSceneMouseEvent *event)
{
    if(event->button() == Qt::LeftButton)
    {
        timer->start();
    }
}

和我班的头：

#ifndef TIMELINE_H
#define TIMELINE_H

#include <QObject>
#include <QColor>
#include <QRect>
#include <QGraphicsRectItem>
#include <QPainter>
#include <QGraphicsSceneMouseEvent>
#include "timers.h"

class TimeLine: public QGraphicsRectItem
{
public:
    TimeLine(Timers *t);
    QRectF boundingRect() const;

    void paint(QPainter * painter, const QStyleOptionGraphicsItem * option, QWidget * widget);

    float timeLineScale;
    int timeLineWidth;
    void mousePressEvent(QGraphicsSceneMouseEvent * event);

private:
    Timers *timer;

protected:

    void mouseReleaseEvent(QGraphicsSceneMouseEvent * event);


};

#endif // TRACK_H

最佳答案

问题是由覆盖boundingRect()方法引起的，如何从QGraphicsRectItem继承，使用setRect()是正确的

时间线

#ifndef TIMELINE_H
#define TIMELINE_H

#include "timers.h"
#include <QGraphicsRectItem>

class TimeLine : public QGraphicsRectItem
{
public:
    TimeLine(Timers *t, QGraphicsItem *parent = 0);
    void paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget);
protected:
    void mousePressEvent(QGraphicsSceneMouseEvent *event);
private:
    int timeLineWidth;
    float timeLineScale;
    Timers *timer;
};

#endif // TIMELINE_H

timeline.cpp

#include "timeline.h"

#include <QGraphicsSceneMouseEvent>
#include <QPainter>
#include <QTimer>

TimeLine::TimeLine(Timers *t, QGraphicsItem *parent):QGraphicsRectItem(parent)
{
    timer = t;
    timeLineWidth=200000;
    setRect(QRectF(0,0,timeLineWidth,18));
    timeLineScale = 0.1;

}

void TimeLine::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget)
{
    Q_UNUSED(option)
    Q_UNUSED(widget)
    QRectF rect = boundingRect().toRect();

    QPen pen(Qt::NoPen);
    painter->setPen(pen);
    painter->setBrush(QColor(200,200,200));
    painter->drawRect(rect);

    painter->setPen(Qt::red);
    for(int i=0;i<200;i++)
    {
        painter->drawText(i*30,9,QString::number(i+1));
    }
}


void TimeLine::mousePressEvent(QGraphicsSceneMouseEvent *event)
{
    if(event->button() == Qt::LeftButton)
        timer->start();
}

注意：不必在TimeLine中创建计时器：timer = new Timers;因为之后您将更改指针的方向，因此除了不必要的空间之外，该空间不可用。

在下面的link中，您将找到用于测试功能的项目。

关于c++ - 不调用QGraphicsSceneMouseEvent，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/47328152/